Concrete tamping device



D. HARTl Aug. 29, 1967 CONCRETE TAMPING DEVICE Filed April vl2, 1965United States Patent O 3,338,144 CONCRETE TAMPING DEVICE Duane Hart,2209 Miner, Costa Mesa, Calif. 92627 Filed Apr. 12, 1965, Ser. No.447,328 1 Claim. (Cl. 94-48) This invention relates to concrete surfacetreating devices and methods and more particularly to a device fortamping a concrete surface.

In the process of finishing concrete after the concrete is rst depositedupon a subgrade from a mixing machine in a suitable manner it isnecessary to subject the surface to a series of treatments to provide asmooth and finished surface. An extremely important surface treatment isa thorough and even tamping to displace the coarse aggregate a suicientdepth below the concrete surface and allow the fine materials to rise tothe surface.

Since concrete contains coarse aggregate of varying sizes and shapes adesirable tamping treatment should include a provision for handlingdifferent size aggregate. In this way all of the aggregate, large andsmall, might be proportioned in the concrete at a suiiicient depth toprovide the desired even and smooth surface.

All presently known devices for tamping concrete surfaces sulfer asingle but significant disadvantage in that they are designed to handleonly one size aggregate. A typical tamper consists of a metal grid whichthe operator continuously presses into the surface of the concrete todisplace the coarse aggregate. The holes in the grid are of equal sizewhich means that either they are too small for the larger size coarseaggregate or too large for the smaller size aggregate. In the case of asmall size grid, the tamper has great diiculty in penetrating to anysignificant depth due to difficulty in pushing all sizes of coarseaggregate at once. In addition upward movement of the grid creates asuction force which draws the coarse aggregate up. In the case of alarge size grid, the medium size coarse aggregate remains near thesurface providing an uneven concrete surface. Regardless of the size ofthe grid, prior art tampers were unable to provide the proper depth ofcoarse aggregate. It is accordingly an object of this invention toprovide a tamper for displacing coarse aggregate below the surface ofconcrete.

The tamping device of this invention tamps a concrete surface in amanner to provide a displacement of coarse aggregate below the surfaceof the concrete. A highly vertical penetration of the concrete isobtained by a tamper having a plurality of grid sections of varying sizeholes. A selected surface area is tamped in a series of steps with eacharea being successively subjected to a grid section of different sizeholes. In the first step the largest size aggregate is pushed downwardfrom the surface leaving the medium and smaller size aggregate near thesurface. In succeeding steps the smaller size aggregate is pusheddownward. At the end of the operation on a selected area the coarseaggregate is displaced to a sucient depth allowing the line aggregate torise to provide a smooth concrete surface.

It is therefore another object of this invention to provide an improvedtamping device for displacing coarse aggregate below a concrete surfacewhile allowing iine materials to rise toward the surface.

It is another object of this invention to provide a concrete tampingdevice which operates successively on different size coarse aggregate.

It is still another object of this invention to provide a concretetamping device which impresses a grid of varying size holes On aconcrete surface.

It is a further object of this invention to provide a concrete tampingdevice for achieving a highly vertical penetration ofthe concretesurface.

3,338,144 Patented Aug. 29, 1967 It is a still further object of thisinvention to provide a tamper which displaces coarse aggregate as itpenetrates the concrete surface and allows fine aggregate to rise towardthe surface without a suction effect on the coarse aggregate.

Other objects of the invention will become apparent from theaccompanying specification read with the drawing, in which:

FIGURE 1 is a view in perspective of a tamper in accordance with oneaspect of the invention.

FIGURE 2 is an elevation view of the tamper of FIG. 1 illustrating theoperation of the tamper on a concrete surface, and

FIGURES 3a, 3b, and 3c are elevation views illustrating the step by stepoperation of a tamper according to the invention over a selected surfacearea.

According to a principal aspect of the invention there is provided aconcrete surface treating device for tamping a concrete surface. Thedevice comprises a plurality of grid sections, each having differentsize holes for displacing different size coarse aggregate. By a seriesof steps corresponding to the number of grid sections, a selectedportion of a concrete surface is successively tamped by each of thedifferent size grid sections. A highly vertical penetration of maximumdepth is realized by each of the grid sections driving the coarseaggregate downward while causing the fine aggregate to rise. In thismanner the coarse aggregate is displaced to a maximum depth below theconcrete surface. l

Referring now to the drawing and in particular to FIG. 1 there isillustrated a specific embodiment of the tamper of the invention. In theperspective view of FIG. 1 a tamper 21 consists of three grid sections11, 12 and 13, each of which has successively smaller size holescommencing with the large holes of the section 11. The grid sections 11,12, and 13 are integrally joined in a single structure which may beenclosed by a support frame I15. A handle structure 16 having a pair ofvertically extending tubes 17 and 18 has its lower portion in the formof a pair of arcs 19 and 2l) joining the ends of the support frame 15 bya suitable technique such as welding. The upper portion of the structure16 may have a pair of handle bars 21 and 22 extending and adapted to litthe hands of an operator. The grid sections 11, 12, and 13 aresuccessively greater in depth commencing with the section 11 which hasthe larger size holes. The grid sections 11, 12, and 13 preferably havesquare holes to minimize the exposed structural area. The sides formingthe holes highly vertical. The grid sections may be constructed of ametallic material to provide strength and durability and may also bemade of a plastic material to minimize the adherence of concrete to thesections.

As seen in the elevational view of FIG. 2 the grid section 11 has thelargest size holes and the greatest depth with the succeeding sections12 and 13 having progressively smaller holes and depth of penetration.The grid section 11 pushes coarse aggregate of large size below thedepth A, while the sections 12 and 13 push aggregate to depths ybelow Band C respectively. Thus the tamper 21 operates on varying sizes ofaggregate with different depths of penetration.

Referring now to FIG. 3 there is illustrated in FIGS. 3a, 3b, and 3c,the successive tamping in a series of three steps of a 'concrete surfaceportion enclosed by P. The surface P is irst penetrated by the tamper 21in FIG. 3a with the grid section 11 penetrating the surface to a `depthIof A pushing the coarse aggregate `of larger size than the holes insection 11 below the depth A. The smaller size coarse aggregate are notdisplaced. In the next step as seen in FIG. 3b the grid section 12penetrates theportion P to a depth B pushing the middle size coarseaggregate downward. The grid section 13 containing the smallest sizeholes penetrates the portion' P during the nal step pushing smaller sizecoarse aggregate downward below the depth C.

A significant advantage of the tamping device of the invention lies inthe smooth concrete linish realized after the tamping. Because of thevertical sides of the grid sections and the depth of penetration of thelarger grid sections, there is .no suction on the concrete when thetatmper is raised.

The embodiment illustrated shows a grid with crosssectional sidesforming holes. It is to be noted that if desired the grid may lconsist:of parallel sides only with elongated holes equal to the length of thetamper lbeing formed. Thus, the grid section 11 would comprise a numherof vertical thin plates in parallel and spaced to displace the largesize coarse aggregate. Grids 12 and 13 would have less depth and spacingto t the smaller size aggregate.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample only and is not to be taken by way of limitation, the spirit andscope of this invention being limit-ed only by the terms of the appendedclaim.

I claim:

In a tamping device for treating a concrete sunface,

a plurality of grid sections joined to form a tamper,

each of said grid sections having a predetermined depth of penetrationwhen placed on said concrete surface,

said Vgrid sections joined to form successively different size holes andsuccessively different depths of penetration in sequential alignment,each said grid sections having the largest size hole and longest depthof penetration being at one end of said device and said `grid sectionhaving the smallest size hole and shortest depth of penetration being atthe Iother end of said device,

whereby lwhen each grid section is applied to a selected portion of saidIconcrete surface a different size `of icoarse aggregate is displaced toa different depth.

References Cited UNITED STATES PATENTS 2,740,336 4/1956 Degen 94-48 25JACOB L. NACKENOFF, Primary Examiner.

